Hyperemesis Gravidarum

Question 1

Definition

Answer 1

Onset of intractable nausea and vomiting in first trimester, associated with dehydration, electrolyte imbalance and weight loss

Question 2

Incidence

Answer 2

3% of pregnancies

Question 3

Pathogenesis

Answer 3

• Disease severity related to bhCG levels
• High bhCG results in elevated T4 and suppressed TSH which have been implicated as possible causes of symptoms
  o bhCG and TSH share common alpha-subunit
• Hormonal alterations in oesophageal pressure and gastric emptying may exacerbate symptoms

Question 4

Relevant features on History

Answer 4

o Onset in first trimester (weeks 6-7)
- Ensure symptoms did not preceed pregnancy
o Symptoms of hyperthyroidism (agitation, palpitations, tremor)
o Weight loss >5% prepregnancy weight
o Urinary symptoms (Ddx UTI)
o Absence of abdominal pain – if present consider cholecystitis/pancreatitis
o Medications – ie iron supplements (cause nausea)

Question 5

Relevant examination findings

Answer 5

o Vitals, weight, BMI
o BP – assess for postural drop
o General appearance – muscle wasting
o Cardiovascular examination
o Thyroid examination – goitre, lid lag, reflexes
o Urine dipstick – ketones, leukocytes, nitrites
o Random BSL

Question 6

Relevant Investigations

Answer 6

o Bloods
- FBE
* Elevated haematocrit
- UEC
* Hyponatraemia, hypokalaemia, low urea, metabolic alkalosis
- LFTs
* Abnormal in 50% of cases
- TFTs
* Usually elevated T4, low TSH
- Lipase
o Urine
- Ketonuria
- MCS
o Ultrasound
- Confirm gestational age
- Diagnose multiple pregnancy
- Exclude molar pregnancy
* Ultimately a diagnosis of exclusion

Question 7

Complications of HG

Answer 7

• Maternal
  o Nutritional deficiency
• Wernicke’s encephalopathy
• B1 (thiamine) deficiency
• Presents with neurological symptoms such as blurred vision, confusion, memory impairment
• If retrograde amnesia occurs, may have permanent deficit
• On examination – nystagmus, ataxia, hyporeflexia
• Diagnosis made clinically and confirmed on MRI
• Hyponatraemia
• Presents with lethargy, seizures, respiratory arrest
• Risk of cerebral pontine myelinolysis if correction too rapid
• B6 and B12 deficiencies common
• Weight loss and muscle wasting
  o Protracted vomiting
• Mallory-Weiss tear
• Oesophageal rupture
• Pneumothorax
  o Dehydration
• Haemoconcentration increases risk of VTE
• Renal failure due to pre-renal cause
  o Mental health
• Significant emotional burden of severe HG, especially when admission required
• Often frustration directed at pregnancy and termination may be requested
• Fetal
  o Increased risk IUGR in women with severe HG
  o Wernicke’s encephalopathy associated with 40% incidence of fetal death

Question 8

Management of HG

Answer 8

• Inpatient or outpatient management depending on severity
• General advice
  o Small frequent meals
  o Discontinue supplements if causing nausea
• IV rehydration and electrolyte replacement
  o 2L stat if planned outpatient management, or 3L/day if admission
  o May require 30mmol KCl with rehydration
  o Avoid solutions containing dextrose as may precipitate Wernicke’s
• Medical management
  o First line
• Pyridoxine 25mg QID
• Vitamin B6
• Doxalymine (Restavit) 12.5-25mg bd
• Antihistamine
• Drowsiness
• Metoclopramide (Maxolon) 10mg tds
• Dopamine antagonist
• Risk of extrapyramidal side effects
• Prochlorperazine (Stemetil) 5mg tds or chlorpromazine (Largactil) 10- 25mg qid
• Phenothiazines
• Drowsiness
• Ranitidine 150mg bd
• When accompanying oesophagitis/gastritis

o Second line
- Ondansetron
* 4-8mg tds
- Domperidone

• Maintain nutrition
  o Oral thiamine supplementation 100mg daily
  o Give IV if severe HG
• Prevent DVT
  o Prophylactic clexane for all admitted patients
• Referrals
  o Dietician
  o Mental health team
• Refractory cases
  o Corticosteroids
• Reserve for severe cases where treatment with IVT and parenteral antiemetics has failed
• Prednisolone 25mg bd starting dose
  o Enteral feeding
• When all above treatments fail and there is significant weight loss or abnormal LFTs
• Preferable to parenteral feeding when GI tract usable
• NG or NJ or PEG tube may be used
• Monitor for refeeding syndrome
  o Total parenteral nutrition
• Feeding via PICC line often better tolerated than enteral but carries greater risks
• High risk metabolic/infections complications
• Thiamine supplementation mandatory
• Used for life threatening cases